WordPress has a built-in media manager where you can access your media library, add new files and delete individual files. You can find the media manager by clicking Media → Library, or upload new files by clicking Add New. To remove a file, you will need to select the file and click "Delete Permanently."
The media manager provides a easy-to-use option for managing your media files, viewing file data, what posts it is attached and so forth. If you need to upload large files, Contact support to have your upload limit of 10 MB adjusted.